All-Optical Time Slice Switching Method and System Based on Time Synchronization

2. The method according to claim 1 , further comprising: obtaining a time signal by each optical switching node from a time server to synchronize a local time of the optical switching node, wherein the time server determines the time signal via a satellite or a network.

3. The method according to claim 1 , further comprising: if a state of time slots on a wavelength link changes, transmitting information of the time slots within a period on the wavelength link throughout the optical network by optical switching nodes at each end of the wavelength link so as to determine time slots available to the OTSS connection according to a changed state of the time slots, wherein the information comprises start/end time of time slices, slot occupying/releasing and services carried on time slices.

4. The method according to claim 1 , wherein establishing the OTSS connection comprises: transmitting a message for reserving time slots and information on the available path, the available wavelength and the start/end time of one or more groups of periodic time slots to be occupied on each wavelength link of the available path to other optical switching nodes on the available path by the source node until the message is received by the destination node or a failure occurs; after the message is received by the other optical switching nodes on the available path, reserving the periodic time slots by each optical switching node other than the destination node on the available path for the output fiber port connected to a next optical switching node on the available path according to the information on the available path, the available wavelength and the start/end time of one or more groups of periodic time slots to be occupied on each wavelength link of the available path, wherein reserved time slots are not allowed to be occupied by other connections within a reserved period; after the message is received by the destination node, transmitting a confirming message on the available path by the destination node until the confirming message is received by the source node; after receiving the confirming message, configuring the optical switch controller by each optical switching node other than the destination node on the available path, wherein configuring the optical switch controller comprises setting periodic switching points according to the start/end time of one or more groups of periodic time slots to be occupied on each wavelength link of the available path.

5. The method according to claim 4 , wherein transmitting data streams to the destination node via the OTSS connection by the source node comprises: recoding the data streams by the source node to obtain recoded data streams according to a line rate of a wavelength channel on the available path, wherein recoding the data streams comprises remodulating the data streams and assembling them into an OTSS sub-wavelength optical channel according to the start/end time of one or more groups of periodic time slots to be occupied on the first wavelength link of the available path; transmitting the recoded data streams to a next optical switching node on the available path by the source node at the start time of one or more groups of periodic time slots to be occupied on the first wavelength link of the available path; switching optical switches by each optical switching node on the available path at the switching points set by the optical switch controller to switch periodic time slices arriving at the input fiber port to the output fiber port.

6. The method according to claim 1 , wherein determining the start/end time of one or more groups of periodic time slots to be occupied on each wavelength link of the available path comprises: selecting one or more groups of periodic available time slots ψ o =∪ n=1 N (t n start ,t n end ) from the combined available time slots on the available path as one or more groups of periodic available time slots to be occupied on a first wavelength link of which a total data transmission bandwidth is greater than or equal to the requested bandwidth, where t n start , t n end and N represent a start/end time of an n th available time slot on the first wavelength link and a number of available time slots on the first wavelength link respectively; if there are more than one wavelength links on the available path, calculating start/end time of one or more groups of periodic time slots to be occupied on other wavelength links of the available path according to one or more groups of periodic available time slots to be occupied on the first wavelength link as: t j n start ⟵ t n start + ∑ k = 1 j - 1 ⁢ T d k , t j n end ⟵ t n end + ∑ k = 1 j - 1 ⁢ T d k , where t j n start and t j n end represent a start/end time of an n th available time slot on wavelength link e j respectively, j=2˜H 2 , H 2 is a number of wavelength links of the available path and T d k is a propagation delay of wavelength link e k .

7. The method according to claim 1 , wherein time slices are separated from each other by a guard time and the method further comprises: when a time synchronization error or a propagation delay variation exceeds the guard time so that a conflict between time slices occurs, delaying the time slices by an apparatus in an electrical domain or an optical domain at output fiber ports of conflicting optical switching nodes.